In many food processing operations, such as in the processing of fruit and vegetable products, the food product must be heated and maintained at a sterilizing temperature and then cooled sufficiently to allow further packaging and transport. After proper heat sterilization, the product is either cooled and then packaged under aseptic conditions, or the product is immediately packaged in a heated, sterile condition and then cooled to a temperature sufficient for additional packaging and shipping. The product may also be packed cold in a container, and then sealed, sterilized and cooled in the container. Cooling the sterilized food product while the product is sealed within a container, such as a flexible bag, eliminates the need for filling sterile bags with cooled, sterile food product under aseptic conditions. Instead, the bag may be filled with heated, sterilized food product and sealed to ensure that the food product remains sterile. To achieve acceptable cooling times, complex cooling equipment has generally been designed to accommodate specific package types. On the other hand, simpler conveying systems that merely spray the packages with chilled liquid result in longer cooling times and, therefore, higher processing costs.
Many different systems have been proposed and used for continuously heating and/or cooling containers of food product along a moving production line. As mentioned above, some of the more complex systems include mechanisms or structure for agitating the food contents as the containers are heated or cooled by liquid or gas heat transfer media. For example, cans of liquid-based food product have been agitated back and forth or rolled as a conveyor moves the cans past nozzles that spray the cans with a heat transfer liquid. With other equipment, pouches or bags have been manipulated by rollers or rocked back and forth on specialized carriers while the pouches are conveyed through a heat transfer media.
To address various problems of the past, it would be desirable to provide apparatus and methods for heating and/or cooling product quickly and uniformly, whether the product is packaged in a rigid or flexible container.